* configure.ac: Check for Linux device-mapper support.

* util/hostdisk.c (device_is_mapped): New function.
(find_partition_start): New function, partly broken out from
linux_find_partition and grub_util_biosdisk_get_grub_dev but with
device-mapper support added.
(linux_find_partition): Use find_partition_start.
(convert_system_partition_to_system_disk): Add `st' argument.
Support Linux /dev/mapper/* devices if device-mapper support is
available; only DM-RAID devices are understood at present.
(find_system_device): Add `st' argument.  Pass it to
convert_system_partition_to_system_disk.
(grub_util_biosdisk_get_grub_dev): Pass stat result to
find_system_device and convert_system_partition_to_system_disk.  Use
find_partition_start.
* conf/common.rmk (grub_mkdevicemap_SOURCES): Add kern/env.c,
kern/err.c, kern/list.c, kern/misc.c, and kern/emu/mm.c.
* util/deviceiter.c [__linux__]: Define MINOR.
(grub_util_iterate_devices): Add support for DM-RAID disk devices.
* util/mkdevicemap.c (grub_putchar): New function.
(grub_getkey): New function.
(grub_refresh): New function.
(main): Set debug=all if -v -v is used.

configure.ac

@@ -780,6 +780,22 @@ AC_SUBST([enable_grub_mkfont])
 AC_SUBST([freetype_cflags])
 AC_SUBST([freetype_libs])
 
+AC_ARG_ENABLE([device-mapper],
+              [AS_HELP_STRING([--enable-device-mapper],
+                              [enable Linux device-mapper support (default=guessed)])])
+if test x"$enable_device_mapper" = xno ; then
+  device_mapper_excuse="explicitly disabled"
+fi
+
+if test x"$device_mapper_excuse" = x ; then
+  # Check for device-mapper library.
+  AC_CHECK_LIB([devmapper], [dm_task_create],
+               [LDFLAGS="$LDFLAGS -ldevmapper"
+                AC_DEFINE([HAVE_DEVICE_MAPPER], [1],
+                          [Define to 1 if you have the devmapper library.])],
+               [device_mapper_excuse="need devmapper library"])
+fi
+
 AC_SUBST(ASFLAGS)
 
 # Output files.